The high speed or rapid transit system is becoming increasingly popular for moving relatively large masses of people between towns and into cities. The electrically driven rail cars are fast, quiet, comfortable and don't contribute to air pollutions that threatens large metropolitan areas. Mechanically, the rail cars used by the rapid transit systems are light weight and powerful enough for use in reasonably hilly areas. However, one of their drawbacks is that their light weight and high speed gives them a tendency to slip on their rails when brakes are applied, or when starting from a stop to climb a grade.
Slipping on the rails when brakes are applied is not the fault of the brakes since the combination of electrical braking, which is used to slow the rail cars from a high speed, and mechanical braking after the cars have been slowed, is quite adequate. The slippage is due to the interface of a steel wheel on a steel rail. This slippage is not found in the much slower "trolley" or street cars, nor in the very heavy locomotives during braking because their weight demands a gradual slowing when stopping.
The high speed, light weight rail cars accelerate quickly to speeds up to about 80 miles per hour and are designed to achieve a deceleration rate of about 3 miles per hour per second (3 mi/hr/sec) when stopping. This deceleration rate is obtainable from a fairly low speeds of perhaps 35 miles per hour but as the speed is increased, the deceleration rate decreases so that at a speed of around 70 miles an hour, the rate may have dropped to 2 mi/hr/sec. If any attempt is made to slow down faster, it probably will result in a skid along the rails.
Another factor contributing to skidding is a track that is wet or frosty. When this occurs, a deceleration rate much less that 2 mi/hr/sec results. Therefore, while the brakes function properly and can easily stop the wheels from rotating, something is needed that makes the decelerating rotating steel wheels adhere to the steel rails. This is the function of the present invention.
The fundamental object of the invention is to improve adhesion between a steel rail and a steel wheel on a rail car for preventing or reducing skidding. This becomes exceedingly important when a rail car is approaching a stop at the bottom of a grade or climbing a grade after having stopped at the bottom. Improving adhesion between rail and wheels will result in faster trains with faster stops and therefore the passage or more passengers per hour.
Briefly described, the present invention is for a magnetic rail that may be installed along areas where rail skidding normally occurs. The preferably electromagnetic rail, when energized, will forcibly attract the steel wheel to it to prevent any slippage between them during braking of acceleration of the wheel.